Detection, characterization and conservation of evolutionarily isolated species

Most published phylogenetic trees are imbalanced, meaning that while many species have many close relatives a minority have few. Importantly, these few isolated species have few closely-related species with which they can share the burden of their slice of the world's biodiversity, i.e. they are non-redundant. Of the ten or so published measures of evolutionary isolation, several overlap in the information they contain and therefore need not be used concurrently in analyses. Interestingly, isolated species that score highly using many such measures are generally overdispersed in a phylogeny, and therefore might collectively represent the shared branches contained within that phylogeny. This property is important if we consider isolated species as targets for increased conservation attention under an 'agony of choice' framework. One way to target them is using the novel 'expected loss' method, which multiplies our 'value' measure (evolutionary isolation) with an 'urgency' rating (threat of extinction) to prioritise those species that are both isolated and threatened. I show that evolutionary isolation and expected loss in primates is correlated with how far from the mean a species scores for many different biological, ecological and geographical traits, suggesting perhaps some link between evolutionary isolation and ecological distinctiveness. Lastly, evolutionarily isolated species are, in general, found in the most species rich areas of the world with geographic isolation playing a limited role in explaining their distribution. Overall, evolutionarily isolated species are both phylogenetically infrequent and morphologically unusual suggesting they may well warrant greater future conservation attention